Fluid pressure electrical switch



Dec. 18, 1945. N 2,391,068

FLUID PRESSURE ELECTRICAL SWITCH Filed July 29, 1943 2 Sheets-Sheet 1A\\ II I E 25 27 5 5 an as 23 .3 We .3 can 9 J INVENTOR Dec. 18, 1945. VJ. M. NYE I 2,391,068

FLUID PRESSURE ELECTRICAL SWITCH Filed July 29, 1943 2 Sheets-Sheet 2 mgWA INVENTOR J. M. NYE

ATT' NEYS I Bourdon type device Patented Dec. 18, 1945 2,391,068 FLUIDPRESSURE ELEGIRIOAL swrron J. Marshall Nye, Phillips, Tex., assignor toPhillips Petroleum Company, a corporation of Delaware Application July29, 1943, Serial No. 496,660

8 Claims. (01. zoo-as) This invention relates to pressure operatedswitches and it has particular relation to electrical switches operatedby pressure of fluids containing solidifiable, congealable orprecipitatable solid matter.

One object of this invention is to operate a I switch by means ofpressure in a fluid which contains paraflln or other congealing orprecipitating solid materials which would plug the tube of a Bourdongage.

Another object of my invention is to adopt such a pressure transmittingmeans as set forth in the above paragraph to a magnetrol electricalswitch.

Another object of my invention is to provide a pair of barriers to theescape of fluid so that if the fluid penetrates the diaphragm it willnot escape from the device and will not reach the electrical switchwhere it would cause fire or other damage.

Another object of my invention is to provide a device which will operateunder high pressure and under adverse conditions.

Other objects of my invention are to provide a self contained pressureswitch unit which will not leak, get out of order, or be influenced byoutside factors and in which the parts are simple in operation andconstruction'and' easy to replace g or repair.

Further objects will be obvious to those skilled in the art from readingthe specification and the claims and from looking at the figures of thedrawings.

Much trouble has been caused in the prior art of pressure switches whenused on petroleum pipes because the tube leading to the pressure switchbecame plugged with paraffin or congealing oil. oftentimes the diaphragmwould fall, releasing the oil or gas where it would reach the electricalswitch and catch fire. Such fires have resulted in destruction ofvaluable property. The switches of the prior art contain material partswhich were stressedrepeatedly and which crystallized and broke underconditions of fatigue.

Applicant has avoided the difficulties of the prior art by providing apressure transmitting device for the electrical switch which has a largeopening which can not be clogged with paraflin and in which failure ofthe diaphragm will not result in a fire. As there is no material tofatigue or crystallize or any springs to break after repeated flexing,the diificulties of the prior art are avoided. The inaccurate operationof the in which the tube becomes sprung out of shape after long use isavoided.

In the drawings:

Figure 1 is an elevational view mainly in cross section of anillustrative embodiment of my invention showing one type of electricalswitch employed.

Figure 2 is an elevational view of a modification of my invention shownmainly in cross section and with parts broken away.

In Figure 1, a large diameter pipe 3 may be connected in any desiredmanner to a pipe, tank, or other apparatus (not shown) containing oil orother fluid, such as a gas containing suspended precipitatable material,tending .to congeal or precipitate solids. Pipe 3 ends in a flange 4 onwhich a flexible diaphragm 5 is supported. This diaphragm may be made ofrubber, or of neoprene or any flexible substance preferably resistant toattack by the fluid used. Flexibility is essential and together withresistance to the fluids it is exposed towill result in long life. Dia-=phragm 5 is preferably of a diameter substantially greater than would beplugged with precipitates between normally spaced overhauling tours, and

for some paraifins is several inches in diameter""" Secured to flange 4to bolts 5 andnutS-l -and,., holding down diaphragm 5 is pressurechamber 8. A screw plug 9 is provided for varying the volume of thepressure chamber as it is screwed in or out of the chamber. A conduit l0and valve II are provided to supply or remove fluid from chamber 8.

Closing the top of chamber ii and secured thereto by bolts l2 and nutsI3 is an electrical switch housing base Ml. Welded to the centralportion of the base is an inverted cylindrical cup member it: which isbest seen in Figure 2. Secured to the lower side of base M by screws iiiis an annular guide member El.

Returning to Figure 1 there is shown in cham her 8 a rod l8 whichengages diaphragm 5 b. means of shoe i9. Shoe i9 is carried up and downby diaphragm as the pressure in pipe 3 varies, and rod l8 moving withshoe i9 is guided in annular guide 0?. I

The upper end of rod I8 is provided with lock nuts 20 (as shown inFigure 2 or similar rod 35) and freely sliding on rod [8 there is asleeve 2i. Rod l8, nuts 20 and cup :15 are made of nonmagnetic materialsuch as brass, while sleeve 2| is made of iron or steel.

In the top of cup is a screw threaded socket 22. In Figure 1 anelectrical switch housing 23 rests on'an external annular shoulder ofbase it and. is. held down by acorn nut 21; threaded screwing intosocket 22. I

Resting on the top of cup i5 and surrounding the threaded rod 25 is anannular disk of fiber 26 which provides an insulating electricalconnecting block for electric cable 21 and electrical wires 28, 28 and30. The plate 26 is held down by lock nuts 3|. Secured to the cup l5 bya split collar 3|, 32 which is clamped together by screw 33, is amagnetic mercury switch 34. The switch 34 is pivoted at 35 and has anAlnico permanent magnet 38 secured to it rigidly. Also secured to itrigidly by bands 31 is a mercury switch 38 containing 2 drops ofmercury, a large drop 38 and a small drop 40. Wires 28, 29 and 30 leadup into the drops of mercury in tube 38. The usual electrical conduit 4|may be provided to protect c'alble 27.

In Figure 2 member 3 is shown connected to a larger member 42 which maybe the wall of a tank by means of nipple 43 which is welded at 46 tomember 42.

Instead of a shoe I9 on the bottom of rod l8 as shown in Figure l, inFigure 2 the rod 55 which corresponds to rod I8 is provided at its lowerend with a float 46 which floats on the surface of liquid 41 in pressurechamber 8.

The operation of the device is as follows:

In Figure 1,'fluid pressure on diaphragm 5 from the lower side willforce rod l8 up into cup IS.

The pressure at which operations take place may be varied by adjustingscrew 9 and by putting float 35 and moving rod 115 into cup IS. Thelevelof liquid 4! may be varied to adjust the height of 416 by additionsor subtractions through conduit is and a gas under pressure may beplaced over the liquid W in chamber 8 to increase the pressure necessaryto operate the switch.

In 'both Figures 1 and 2, sleeve 2| is raised inside of cup l5, andsleeve 2| being of magnetic material will attract permanent magnet 36through the brass cup 85. Magnet 36 moves nearer to and beside sleeve 2|turning the switch about pivot 35 and spilling the large drop of mercuryfrom 39 over to 60. This connects wires 28 and 29 and disconnects wires29 and 30.

As rod l8 or 45 descends when pressure'on diaphragm 5 is reduced, sleeve2| remains behind, stationary relative to magnet 36 until the upper locknuts 20 strike the top of the sleeve and force the sleeve away from themagnet. Then the magnet no longer being attracted allows the mercuryswitch to fall back in the position shown in Figure 1. The space betweennuts 20 allows sleeve 2| to have some free movement providing apredetermined range of pressures on diaphragm 5 without continuallyopening and closing switch 33.

It is therefore obvious that I have produced a novel and useful devicefor the transmission of pressure forces to switches, and obviously minorchanges may be made without departing from my invention as set forth inthe following claims.

Having described my invention, I claim:

1. A fluid pressure actuation means for an electrical switch comprisingin combination a conduit for conducting a fluid under pressure, a rigidfluid tight chamber of limited volume having an open side communicatingwith the conduit, a flexible diaphragm across the open side of the chambr forming a first sealing means for the conduit, rigid means separatefrom said diaphragm for varying the volume of the chamber, andelectrical switch operating means carried by said flexible dia-' phragm,the contacts of said switch being exterior to said chamber, said chamberformin a second sealing means for the conduit and preventing the escapeof fluid to said contacts upon failure of the flrst sealing means.

2. A fluid pressure actuation means for an electrical switch comprisingin combination a conduit for conducting a fluid under pressure, a rigidfluid tight chamber of limited volume having an open side communicatingwith the conduit, a flexible diaphragm across the open side of thechamber forming a first sealing means for the conduit, means separatefrom said diaphragm for varying the residual air pressure in saidchamber, and electrical switch operating means carried by said flexiblediaphragm, the contacts of said switch being outside said chamber, saidchamber forming a second sealing means for the conduit and preventingthe escape of fluid to said switch contacts upon failure of the firstsealing means.

3. A fluid pressure actuation means for an electrical switch comprisingin combination a conduit for conducting a fluid under pressure, a rigidfluid tight chamber of limited volume having a single open sidecommunicating with the conduit, 2. single flexible diaphragm across theopen side of the chamber forming a sealing means for the conduit, alayer of liquid floating on the diaphragm, a float floating on theliquid, an electrical switch operating means carried by said float, saidfluid in said conduit moving said operating means to aposition which isa function of the pressure in said conduit.

4. A fluid pressure actuation means for an electrical switch comprisingin combination a conduit for conducting a fluid under pressure, a rigidfluid tight chamber of limited volume having a single open sidecommunicating with the conduit, a single flexible diaphragm across theopen side of the chamber forming a sealing means for the conduit, alayer of liquid floating on the diaphragm, a float floating on theliquid, means for varying the air pressure in the chamber, andelectrical switch operating means carried by said float, said fluid insaid conduit moving said operating means to a position which is afunction of the pressure in said conduit.

5. A magnetic pressure switch comprising in combination a conduit forconducting fluid under pressure, a flexible diaphragm sealing the conduit, a rigid means forming a closed fluid tight chamber having theflexible diaphragm as one wall thereof, a switch outside the conduit andthe chamber, transmission means moved by the flexible diaphragm whenchanges in fluid pressure in the conduit moves the diaphragm, andmagnetic means, comprising elements on the transmission means and theswitch, operating through other walls of the chamber to throw the switchupon substantial change in fluid pressure, said chamber forming a secondsealing means for the conduit and preventing the escape of fluid uponfailure of said diaphragm.

6. The combination set forth in claim 3 in which an electrical switchdisposed outside the conduit and the chamber and adjacent said chamberis actuated by said electrical switch operating means.

7. A fluid pressure operated safety switch for use with inflammablefluids comprising a conduit for infiammabie fluid under pressure, a bodyhav ing a fluid tight chamber communicating with said conduit, aflexible diaphragm impervious to said fluid extending across saidchamber and pro= viding a space sealed from said fluid, magnetic meansin said space moved by said diaphragm, and. an electrical switchdisposed outside said body adjacent said space, said magnetic meansoperating said switch by magnetic force through the fluid tight walls ofsaid cioer in said body, w

whereby said infiammabie fluid cannot come in contact with saidelectrical switch even when said diaphragm fails.

8. The combination set forth in claim '7 in which the electrical switchis further enclosed in a sealed glass container "whereby upon failure 01said diaphragm and failure of said body said in flammable liquid is keptfrom contacting said switch by said glass container.

J. MARSHAIL NYE.

